1. Field of the Invention
This invention relates in general to vehicle seats, and more specifically to a plastic framework for a backrest of a vehicle seat.
2. Description of the Related Art
Vehicular backseat backrests typically comprise a carpeted section attached to a sheet metal back panel that faces the interior of a vehicle trunk. A frame consisting of bended tubes welded together is provided for the structural support of the vehicle backrest. A cushion is formed over the frame and a layer of skin is wrapped over the cushion and the frame.
The frame is typically made from steel or aluminum. Aluminum is lighter weight than steel frames and may be bent to form the backrest frame; however, the shapes are somewhat limited due to the bends in the frame and the resulting points of weaknesses created. Steel frames although stronger than aluminum frames are heavier.
Plastics have been used to form seat structures but current plastic structures cannot meet energy absorption requirements energy nor do they have the necessary stiffness to support the backrests as do current metal frame structures.